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Re: New to perl

by kennethk (Monsignor)
on Mar 14, 2011 at 20:22 UTC ( #893143=note: print w/ replies, xml ) Need Help??


in reply to New to perl

All these 14 Q's are from my last year exam paper i took from library and i am trying to solve them
Thank you for frankly explaining where these questions are coming from. Rather than explicitly answering them, I will give some quick pointers into the docs. Some of these questions are unclear to me; whether that is a problem with your transcription or the original, I cannot say.

  1. Describe the main features of perl .What are its characteristics which makes it suitable for Bioinformatics

    perlintro, http://www.bioperl.org/wiki/HOWTO:Beginners

  2. What is a file handle ? How they are similar to streams

    perlopentut

  3. What are scalar variables ?Discuss various types of variables used in perl with examples.

    perldata

  4. Describe named Unary and file operators with examples.

    perlop

  5. Write a perl program that asks the user to enter a name and a number n and prints the nth letter in the name.

    Hint: substr

  6. what are global and scoped declarations in perl ? Write perl script to explain the same .

    Declarations in perlsyn

  7. How we do loop control with next last and redo ? Where we should use them and where not ?

    Loop Control in perlsyn, redo, last, next

  8. What are regular expressions ? Explain in detail its most important elements ?

    perlre, perlretut

  9. Write a perl program which takes file name as arguments and counts lines in file with (a) Letter X (b) String the

    Everything you need is in the above links

  10. What are subroutines ? How it differs from a procedure ? Explain with example how parameters are passed in subroutines.

    perlsub

  11. Write a perl program which reads a file into a hash array.

    Everything you need is in the above links

  12. Write a perl script which compares and concatenates two strings.

    Everything you need is in the above links

  13. What for formats are used in perl ? How we can access formatting internals ?

    I do not know what this means; do they mean perlguts or perhaps sprintf? Maybe IO Layers?

  14. What are hashes ? Describe all functions relevant to hashes.

    perldata

If you are preparing for a test, where you found an old test in the library, your new test will likely not have the same questions on it; by gaining familiarity with the Perl documentation, you will prepare yourself for the next test, not the previous one.


Comment on Re: New to perl
Re^2: New to perl
by ELISHEVA (Prior) on Mar 14, 2011 at 20:45 UTC
      Better yet, use Perl6::Form, which brings Perl6-style forms to Perl5. Less magical and much cleaner than the builtin forms.
        Well dear friend ikegami, i wanted to directly study answers of my questions...if they were solved. I have problem making conclusion about answer to questions...when i read text related to question then i think is it only the text that i need to write in answer so i asked questions here and today i was making project report so couldn't get time to study these questions.Now i am trying to conclude answers of all 19 questions one by one.Thanks for serving as helping hand and great encouragement. THANKS!
Re^2: New to perl
by Monk_perl on Apr 05, 2011 at 07:52 UTC

    Write a perl program that asks the user to enter a name and a number n and prints the nth letter in the name? Hint: substr

    I read substr but i didn't see how it can be user operated program.

    I think question asks the user to enter value of n to print the letter or character from the string defined in the program.

    i want that program should ask the user on the command line to enter name and number n to print its corresponding letter, isn't it that i think about question ?

      We seem to be going round in circles here. If you do want to learn perl, read and understand the replies you've previously been given, work (yes, work. Don't just read them, make sure you understand what they're saying and how the code works) through the examples given in Getting Started with Perl from the tutorials section. If there is something you don't understand, you're going to have to specifically tell us, otherwise we'll never know.

      My advice would be to stop posting exam questions and actually spend your time learning this. You say you have an exam to do, was there was an associated course? If so you should have notes. Do you have a teacher of some kind you could ask?

      i want that program should ask the user on the command line to enter name and number n to print its corresponding letter, isn't it that i think about question ?
      And I want a pony. But nobody on this website is going to give me one. Does that seem unfair?

      In order to achieve your desired result, you need to break it down to basic steps that are easily programmable - this will be your algorithm. In this case, I would:

      1. Obtain a name from the user, via STDIN (I/O Operators)
      2. Obtain an index from the user, via STDIN
      3. Use substr to obtain the n-th letter of the name
      4. print that character to STDOUT

      If you follow the extensive assistance you received in how to create a perl program using filehandle and streams ?, you should be able to achieve 1. and 2.

      This site is full of people who are patient, friendly and generous with their valuable time - time that is more valuable than yours in a very literal way. Your apparent lack of effort is rapidly burning bridges here. I caution you to consider this before posting again. How do I post a question effectively?.

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